Some private application servers, such as enterprise communication application servers, provide much more communication services than public network communication application servers. Enterprise communication servers typically provide supplementary services such as call recording, video conferencing, consultation calls, transferring, call shifting between a set of user terminal devices, and others.
When a user, who is a registered subscriber of such a private application server, happens to initiate or receive a communication directly through the public network, he is not in position to benefit from the full services of the private application server, e.g. his enterprise application server. For example, the user involved in a mobile communication, managed by a mobile network telephony application server, cannot escalate this communication to a full collaboration session, this escalation capability being only available through his enterprise communication application server, which is not involved in the communication so far.
Therefore, in order to benefit from the supplementary services of the private application server, the user must hang-up the communication and, then, he re-establishes the call using the private application server. To that end, the user needs to choose the private application server, re-find the contact of the other user and establish a new call through the private application server.
Such process is bothersome, time consuming and should therefore be avoided.
FR 2 935 858 discloses a telecommunication method that allows shifting a call established through a server of the public network in order to route it to an enterprise application server. FR 2 935 858 discloses that a first user terminal may send a server shift instruction and that upon a server shift instruction has been received, the public network is instructed to reroute the call towards the enterprise application server.
The public network stops the call with the terminal of the first user, suspends the call with the correspondent device and performs a call towards the enterprise application server. Then, the enterprise application server establishes a call with the terminal of the first user which accepts the call.